There are numerous devices and methods for connecting radio frequency transceivers and cellular radio systems to computers. Among these devices are packet radio stations, packet node networks and Echolink networks.
A basic packet radio station consists of a computer, a modem and a transceiver with an antenna. Traditionally, the computer and modem are combined in one unit, referred to as a terminal node controller (‘TNC’), with a dumb terminal or a computer software terminal emulator, and the combination is used to input and display data.
Advantageously, the TNC of a basic packet radio station works with a modem to convert American Standard Code for Information Interchange (‘ASCII’) codes typed by a user into modulated tones to be broadcast by the RF transceiver and convert demodulated tones received from other packet radio stations back to ASCII to be displayed on the terminal. Further advantageously, the computer formats the transmitted data in a standard AX.25 Internet data packet (‘the data’), and controls the radio channel.
Disadvantageously, however, the basic packet radio station operates in a simplex mode and does not receive and transmit signals simultaneously. Further disadvantageously, the basic packet radio station requires a data parity acknowledgment from the destination station limiting the distance that the data can travel. Further disadvantageously, the AX.25 protocol used to transmit the data in the basic packet radio station is used to establish direct, point-to-point links between packet radio stations, and requires an expensive digipeater to establish communications between two stations unable to communicate directly.
A packet node network is another means of connecting to other packet stations by first connecting to a radio broadcast node or to a digipeater that is in contact with other radio broadcast nodes to communicate with a distant radio station.
Advantageously, the packet node network is very simple to use and can reach greater distances and is compatible with basic packet radio. Further advantageously, each radio broadcast node that the data is routed through acknowledges the data packet as it is sent to the destination station.
Disadvantageously, however, the packet node requires the operator to first directly connect to a local radio broadcast node or local digipeater with good signal strength. Then the operator connects to a first station within range of the radio broadcast node. Next, the first station connects to a non-local radio broadcast node within the first station's communication range. Then the non-local radio broadcast node transmits the typed message to a connected bulletin board system (‘BBS’). The user can also obtain a list of the non-local radio broadcast nodes that are available, check routes of communications between the user and a destination radio broadcast node that is to be contacted and check the status of the user in relation to the local radio broadcast nodes and the non-local radio broadcast nodes. Further disadvantageously, each radio broadcast node must continuously update and broadcast a list of other radio broadcast nodes that can be contacted, thereby diminishing the available bandwidth for radio traffic.
An Echolink network provides a means for worldwide connections to be made between radio stations or from a computer to a radio station that greatly enhances the radio's communications capability.
Advantageously, the Echolink network program provides a method for radio stations to communicate with one another over the Internet, using voice-over-Internet Protocol (‘VoIP’) technology.
Disadvantageously, however, the Echolink network only provides a simplex link or one way communication (i.e., the radio station can transmit radio signals or receive radio signals but not simultaneously). Further disadvantageously, a very high frequency (‘VHF’) or an ultra high frequency (‘UHF’) transceiver must be in range of their station or near a repeater station to communicate with other stations and the receiving station must be similarly-equipped to receive the voice communication.
Therefore, there exists a need for connecting RF transceivers and cellular radio systems to a computer for improving the efficiency and distance of two-way radio communications devices that is not associated with these disadvantages.